Search for arc-produced heterofullerenes

Lamb, John R.,Kwon, Youngwoo,Ruoff, Rodney S.,Lamb, Lowell D. Elsevier 2017 Carbon Vol.119 No.-

<P>Replacing one or more of the carbon atoms in a fullerene cage with one or more non-carbon atoms is expected to result in a structure (heterofullerene) with significantly altered and potentially useful properties. While (C59N)- and (C69N)-based compounds can be synthesized via solution-phase modification of C-60 and C-70, respectively, a general, high-yield method for producing heterofullerenes has not been identified. We report the results of a search for heterofullerenes using atmospheric pressure photo-ionization mass spectrometry on samples of fullerene soot produced in nitrogen and carbon monoxide via the Kratschmer-Huffman arc technique. Contrary to earlier reports, we found no evidence of the presence of heterofullerenes in any of the samples we examined. X-ray photoelectron spectroscopy of fullerene soot produced in nitrogen indicates that while nitrogen is incorporated into the carbon matrix, the observed nitrogen-carbon bonding configurations do not permit the formation of fullerenes. We also report the discovery of production conditions under which argon can be used as a buffer gas and the yield of soluble fullerenes is comparable to the best yield achievable using helium. These findings may shed light on the general problem of the fullerene formation process. (C) 2017 Elsevier Ltd. All rights reserved.</P>

Cadmium solubility and bioavailability in soils amended with acidic and neutral biochar

Qi, Fangjie,Lamb, Dane,Naidu, Ravi,Bolan, Nanthi S.,Yan, Yubo,Ok, Yong Sik,Rahman, Mohammad Mahmudur,Choppala, Girish Elsevier 2018 Science of the Total Environment Vol.610 No.-

<P><B>Abstract</B></P> <P>This study was designed to investigate the effects of acidic and neutral biochars on solubility and bioavailability of cadmium (Cd) in soils with contrasting properties. Four Cd contaminated (50mg/kg) soils (EN: Entisol, AL: Andisol, VE: Vertisol, IN: Inceptisol) were amended with 5% acidic wood shaving biochar (WS, pH=3.25) and neutral chicken litter biochar (CL, pH=7.00). Following a 140-day incubation, the solubility and bioavailability/bioaccessibility of cadmium (Cd) were assessed. Results showed that both biochars had no effect on reducing soluble (pore water) and bioavailable (CaCl<SUB>2</SUB> extractable) Cd for higher sorption capacity soils (AL, IN) while CL biochar reduced those in lower sorption capacity soils (EN, VE) by around 50%. Bioaccessibility of Cd to the human gastric phase (physiologically based extraction test (PBET) extractable) was not altered by the acidic WS biochar but reduced by neutral CL biochar by 18.8%, 29.7%, 18.0% and 8.82% for soil AL, EN, IN and VE, respectively. Both biochars reduced soluble Cd under acidic conditions (toxicity characteristic leaching procedure (TCLP) extractable) significantly in all soils. Pore water pH was the governing factor of Cd solubility among soils. The reduction of Cd solubility and bioavailability/bioaccessibility by CL biochar may be due to surface complexation while the reduced mobility of Cd under acidic conditions (TCLP) by both biochars may result from the redistribution of Cd to less bioavailable soil solid fractions. Hence, if only leaching mitigation of Cd under acidic conditions is required, application of low pH biochars (e.g., WS biochar) may be valuable.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The acidic biochar did not reduce soil soluble/bioavailable/bioaccessible Cd. </LI> <LI> The neutral biochar reduced soluble/bioavailable Cd of low sorption capacity soils. </LI> <LI> The neutral biochar reduced bioaccessible Cd of the four studied soils. </LI> <LI> Both acidic and neutral biochars reduced Cd mobility under acidic conditions. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

A review of two theories of motion sickness and their implications for tall building motion sway

D. Walton,S. Lamb,Kenny C.S. Kwok 한국풍공학회 2011 Wind and Structures, An International Journal (WAS Vol.14 No.6

Low-frequency building vibration is known to induce symptoms of motion sickness in some occupants. This paper examines how the adoption of a theory of motion sickness, in conjunction with a dose-response model might inform the real-world problem of managing and designing standards for tall building motion sway. Building designers require an understanding of human responses to low-dosage motion that is not adequately considered by research into motion sickness. The traditional framework of Sensory Conflict Theory is contrasted with Postural Instability Theory. The most severe responses to motion (i.e., vomiting) are not experienced by occupants of wind-excited buildings. It is predicted that typical response sets to low-dosage motion (sleepiness and fatigue), which has not previously been measured in occupants of tall-buildings, are experienced by building occupants. These low-dose symptoms may either be masked from observation by the activity of occupants or misattributed to the demands of a typical working day. An investigation of the real-world relationship between building motion and the observation of low-dose motion sickness symptoms and a degradation of workplace performance would quantify these effects and reveal whether a greater focus on designing for occupant comfort is needed.

A review of two theories of motion sickness and their implications for tall building motion sway

Walton, D.,Lamb, S.,Kwok, Kenny C.S. Techno-Press 2011 Wind and Structures, An International Journal (WAS Vol.14 No.6

Low-frequency building vibration is known to induce symptoms of motion sickness in some occupants. This paper examines how the adoption of a theory of motion sickness, in conjunction with a dose-response model might inform the real-world problem of managing and designing standards for tall building motion sway. Building designers require an understanding of human responses to low-dosage motion that is not adequately considered by research into motion sickness. The traditional framework of Sensory Conflict Theory is contrasted with Postural Instability Theory. The most severe responses to motion (i.e., vomiting) are not experienced by occupants of wind-excited buildings. It is predicted that typical response sets to low-dosage motion (sleepiness and fatigue), which has not previously been measured in occupants of tall-buildings, are experienced by building occupants. These low-dose symptoms may either be masked from observation by the activity of occupants or misattributed to the demands of a typical working day. An investigation of the real-world relationship between building motion and the observation of low-dose motion sickness symptoms and a degradation of workplace performance would quantify these effects and reveal whether a greater focus on designing for occupant comfort is needed.

Thermal stability of biochar and its effects on cadmium sorption capacity

Qi, Fangjie,Yan, Yubo,Lamb, Dane,Naidu, Ravi,Bolan, Nanthi S.,Liu, Yanju,Ok, Yong Sik,Donne, Scott W.,Semple, Kirk T. Elsevier Applied Science 2017 Bioresource technology Vol.246 No.-

<P><B>Abstract</B></P> <P>In this study, the thermal stability of a wood shaving biochar (WS, 650°C), a chicken litter biochar (CL, 550°C) and an activated carbon (AC, 1100°C) were evaluated by combustion at 375°C for 24h to remove the labile non-carbonized organic matter. Results showed that WS and CL biochars were not thermally stable and can lose most of the organic C during combustion. The combusted WS and CL biochars retained considerable amounts of negative charge and displayed higher sorption for Cd (from 5.46 to 68.9mg/g for WS and from 48.5 to 60.9mg/g for CL). The AC retained 76.5% of its original C and became more negatively chargely after combustion, but its sorption for Cd slightly decreased (from 18.5 to 14.9mg/g). This study indicated that after potential burning in wildfires (200–500°C), biochars could have higher sorption capacity for metals by remaining minerals.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Moderate temperature (550–650°C) biochars contained mostly labile organic C (OC). </LI> <LI> Biochar OC was not thermally stable and easily oxidized by wildfire (200–500°C). </LI> <LI> Combusted (375°C) biochars were mineral dominant and negatively charged. </LI> <LI> Biochar combustion residues showed a higher and stronger sorption capacity for Cd. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Mossbauer Study of nano - sized (Li0.5xFe0.5xZn₁-x)Fe₂O₄ particles

J. C. Sur,T. S. Kim,T. Y. Ha,J. K. Lee,S. H. Gee,Y. K. Hong,M. H. Park,D. W. Erickson,P. J. Lamb 한국자기학회 2002 한국자기학회 학술연구발표회 논문개요집 Vol.12 No.2

Effects of acidic and neutral biochars on properties and cadmium retention of soils

Qi, Fangjie,Dong, Zhaomin,Lamb, Dane,Naidu, Ravi,Bolan, Nanthi S.,Ok, Yong Sik,Liu, Cuixia,Khan, Naser,Johir, M.A.H.,Semple, Kirk T. Elsevier 2017 CHEMOSPHERE - Vol.180 No.-

<P><B>Abstract</B></P> <P>In this study, an acidic biochar and a neutral biochar were applied at 5 wt% into two soils for an 11-month incubation experiment. One Ferrosol soil (Ba) was slightly acidic with low organic matter and the other Dermosol soil (Mt) was slightly alkaline with high organic matter. The acidic (pH = 3.25) wood shaving (WS) biochar had no marked impact on nutrient levels, cation exchange capacity (CEC), pH and acid neutralization capacity (ANC) of either soil. By contrast, the neutral (pH = 7.00) chicken litter (CL) biochar significantly increased major soluble nutrients, pH, ANC of soil Ba. In terms of C storage, 87.9% and 69.5% WS biochar-C can be sequestrated as TOC by soil Ba and Mt, respectively, whereas only 24.0% of CL biochar-C stored in soil Ba and negligible amount in Mt as TOC. Biochars did not have significant effects on soil sorption capacity and sorption reversibility except that CL biochar increased sorption of soil Ba by around 25.4% and decreased desorption by around 50.0%. Overall, the studied acidic C rich WS biochar held little agricultural or remedial values but was favourable for C sequestration. The neutral mineral rich CL biochar may provide short-term agricultural benefit and certain sorption capacities of lower sorption capacity soils, but may be unlikely to result in heightened C sequestration in soils. This is the first study comprehensively examining functions of acidic and neutral biochars for their benefits as a soil amendment and suggests the importance of pre-testing biochars for target purposes prior to their large scale production.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The C rich acidic biochar did not work for nutrients supply or Cd retention but helped in storing C. </LI> <LI> The neutral mineral rich biochar enhanced nutrient and sorption for some soils. </LI> <LI> Neutral mineral rich biochar hardly increased soil C after 11 months. </LI> </UL> </P>

The Stability of PEDOT:PSS Films Monitored by Electron Spin Resonance

이정근,J. M. Cho,R. Lamb,S. J. Moon,신원석,H. Zhang,N. T. Kemp 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.52 No.3

We used electron spin resonance (ESR) and electrical conductivity measurements to track the stability of poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) and ethylene glycol (EG)-treated PEDOT:PSS (EG-PEDOT:PSS) films in air. We observed that the ESR in- tensity of the PEDOT:PSS films decreased in air with oxidation, along with the conductivity. The rate of decrease depended on the thickness of the film. The EG-treated PEDOT:PSS lms showed better stability for both the DC conductivity and the ESR intensity compared with un- treated PEDOT:PSS lms. PEDOT:PSS, oxidized-PEDOT:PSS, and EG-PEDOT:PSS, all showed a symmetric ESR line shape with the same g-value (g = 2.0037), indicative of polarons as the ori- gin of paramagnetic spin resonance. Low-temperature (100 300 K) ESR measurements showed a temperature-independent spin density for all types of samples, in agreement with the metallic phases. The linear temperature-dependent increase of the resonance line width (△Hpp) was mostly ascribable to carrier hopping.